Field of the Invention
The present invention relates to gas supply apparatuses, and particularly to a gas supply apparatus capable of performing functional tests of the digestive tract such as tests for functional dyspepsia (FD) and irritable bowel syndrome (IBS).
Description of the Related Art
It is conventionally known that as one of functional tests for the digestive tract, barostat testing is used for measuring an elastic relaxation response disorder as a disorder of digestive tract motility, which is one of conditions of functional dyspepsia (FD). The barostat testing involves the insertion of a barostat balloon (thin bag made of polyethylene) into a digestive tract such as an intestine and a stomach (stomach fundus in the case of FD) so as to measure a capacity, pressure and compliance of the balloon under computer control. The barostat testing offers an advantage that a digestive tract sensation can be quantitatively evaluated by giving a constant low pressure to the digestive tract.
However, the barostat testing accompanies pain and requires a special instrument. Thus, in recent years, a simpler drink test (indirect evaluation method for evaluating how much a nutritional tonic or water can be taken) is also performed instead of the barostat testing. This drink test, although it is very simple, disadvantageously presents a problem that making a detailed evaluation is difficult.
As described above, conventional functional tests for the digestive tract are inadequate in making a diagnosis of functional dyspepsia (FD) and irritable bowel syndrome (IBS) easily and in detail. Thus, development of an art for dealing with this is desired.
On the other hand, when an endoscope is used to perform an examination or give a treatment, gas is supplied into the body cavity (such as abdominal cavity) of a patient via a gas supply conduit provided on the endoscope so as to ensure the vision of the endoscope and the operation area of a treatment tool. Although air has been mainly used until now as a gas supplied to the body cavity, carbon dioxide (CO2 gas) is increasingly used in recent years. Since carbon dioxide has favorable bioabsorbability, damage suffered by the examinee is less. Consequently, carbon dioxide is increasingly used as a gas supply source.
A gas supply apparatus on which a carbon dioxide-filled gas cylinder is installed is used to supply carbon dioxide into a body cavity. The gas supply apparatus is detachably connected to the gas supply conduit of an endoscope so as to supply pressure-reduced carbon dioxide from the carbon dioxide cylinder.
For example, Japanese Patent Application Laid-Open No. 2007-075518 discloses a gas supply apparatus having a plurality of gas supply modes. The gas supply apparatus includes gas supply modes for abdominal cavities and for subcutaneous spaces, determines whether a surgical instrument which supplies gas is for abdominal cavities or for subcutaneous spaces, switches to a gas supply mode according to the determined result, and controls over supplying a predetermined gas having a pressure and a flow rate in response to the switched gas supply mode. This eliminates the need to manually switch between gas supply settings for abdominal cavities and for subcutaneous spaces depending on the surgical procedure and simplified switching enables the prevention of handling errors.